Heretofore, it has been known that exothermic gas/solid reactions can be carried out in fluidized bed reactors. Such reactors have proven to be highly successful, especially in the preparation of silicon-halogen compounds by the so-called direct synthesis methods, where silicon containing contact masses are reacted with organic halides. The heat of reaction is dissipated through the wall of the reactor with the aid of a heat transfer medium. Also, the same medium is used to convey the heat required to initiate the reaction. (See W. Noll "Chemie und Technologie der Silicone", 1968, Pages 32 and 33).
However, dissipation of the heat of reaction through the reactor wall is not entirely satisfactory and numerous suggestions have been made to improve the process. For example, it has been suggested that heat exchanger conduits be placed inside the reaction chamber (See U.S. Pat. No. 3,133,109). It is generally believed that such conduits should criss-cross in a horizontal direction in order not to adversely affect the distribution of the gas in the fluidized bed. (See "Ullmanns Encyklopadie der technischen Chemie", 4th Edition, 1973, Volume 3, page 486). Because of the abrasion encountered in fluidized bed reactors, especially when very abrasive solid particles such as silica-containing contact masses are employed, the parameters governing the exchanger elements which protrude into the fluidized bed are very limited. For example, tubular heat exchangers having a conventional configuration have proven to be unsatisfactory, since the conduit sections which are arranged in a horizontal position in the fluidized bed with respect to the gas flow are subject to considerable abrasion and any rupturing of the conduits will contaminate the fluidized bed with the heat transfer medium. Up to the present time the problem of removing the heat of reaction through the wall of the reactor has not been solved using the conventional cooling and/or heating jackets. Even those jackets containing semi-circular pipes surrounding the reaction vessel in a serpentine configuration or those consisting of welded-on conduits having angular profiles have not solved the problem, because the heat exchange surface so created is inadequate or the latter cannot be enlarged to the extent necessary because of the additional stress placed on the material used. Thus, it is apparent that a heat exhange apparatus which is more efficient and more resistant to abrasion would be highly desirable for fluidized bed reactors for conducting gas/solid reactions.
Therefore it is an object of this invention to provide a fluidized bed reactor which can be used for gas/solid reactions. Another object of this invention is to provide a fluidized bed reactor which is more efficient in removing the heat evolved from gas/solid reactions. Still another object of this invention is to provide a fluidized bed reactor containing a heat exchange apparatus that is more resistant to abrasion. A further object of this invention is to provide a fluidized bed reactor containing at least one pipe in the reaction chamber and/or a jacket on the outside of the reactor for conveying a heat transfer medium.